J48 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



beginning- at the top a tiny burrow wound down spirally 

 through the structure to one after another of the four or five 

 fresh, clean little nests of green spruce leaf fibers." 



Shelton has described several nests studied by him in the 

 vicinity of Eugene, Oregon. One nest, found approximately 

 100 feet above the ground in a Douglas fir on Spencer Butte, 

 seven miles south of Eugene, was about two feet in diameter 

 by one in depth. It was composed of dry twigs and moss 

 and was beyond all doubt the nest of a gray squirrel (Sciurns 

 griseusj remodeled for Phenacoinys use. The exterior of the 

 nest was wet and mouldy, but the interior was dry and warm. 

 The inner nest was spherical in shape, about five inches in 

 diameter, and composed of fir needle fibers. The nest cavity 

 was within this ball-like structure, and communicated with 

 the outside through a small round opening about an inch in 

 diameter in the wall of the inner nest. A mouse, after tra- 

 versing this opening, would find itself in the coarse outer 

 structure of dry twigs and moss, through which escape was 

 possible in any direction. 



Another nest, found in February by Bovard and Shelton, 

 was located 30 feet up in a Douglas fir. This was a large 

 nest, doubtless originally belonging to a gray squirrel. Its 

 coarse outer structure was of large dry twigs and moss. 

 Within was a large quantity of fibrous material, apparently 

 from the inner bark of the tree, and within this was the inner 

 nest proper, a round ball of the characteristic shredded fibers of 

 the fir leaves. The outer structure was wet and mouldy, and the 

 entire nest was heaped high with piles of rotting feces. In 

 this nest there were taken two young animals, half or two- 

 thirds grown. In the course of the investigation, the nest 

 was entirely dissected away, and there remained nothing of 

 it. Returning to the same locality in June, another nest was 

 found in practically the same crotch. This was a small nest, 

 only eight or 10 inches in diameter, composed of soft moss 

 and the fibers of the fir needles. A small quantity of feces 

 had collected. As Shelton remarks, the indications are that 

 the adult mice, returning and finding their home destroyed, 

 had started a new one of their own construction. Incidentally 

 it should be remarked that this was the only instance noted 

 by Shelton of a nest of original Phenacomys construction. 



